JPH0363696B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a method for detecting bit-to-bit variation information in photoelectric conversion devices such as facsimile machines and copying machines. The present invention relates to a detection method in which the reflected light from the reflective surface is photoelectrically converted multiple times while rotating a paper feed roller to obtain bit-to-bit variation information.

[Prior art] Photoelectric conversion devices using line sensors are commonly used in facsimile machines, copying machines, etc.
The photoelectric characteristics of the photoelectric conversion element array and self-occurring lens array of the above-mentioned line sensor usually have some variation between bits. For this reason, some conventional photoelectric conversion devices are provided with a bit correction circuit for correcting the above-mentioned variations. This bit correction circuit uses a photoelectric conversion element array to read a so-called all-white original, detects the amount of variation in the output in bit units, and then appropriately corrects the bit output based on this detected value. It is something to do.

However, such a method of detecting variation information between bits requires an entirely white original, and it takes time and effort to read this into a photoelectric conversion element array.

Therefore, it is conceivable to form a white reflective surface on the outer peripheral surface of the paper feed roller and use this reflective surface in place of the all-white document described above. It is difficult to obtain a uniform white color.
There is also a problem with reliability when dust or the like adheres to the reflective surface.

[Purpose of the invention]

The present invention was developed in order to effectively solve the above-mentioned problems, and its purpose is to provide a bit detection system in a photoelectric conversion device that can easily and accurately detect dispersion information without using an all-white original. The object of the present invention is to provide a method for detecting variation information between

[Summary of the invention]

The gist of the present invention is to provide a photoelectric conversion device that continuously photoelectrically converts image information on the surface of the document by a photoelectric conversion element array while moving the document illuminated by an illumination light source by a paper feed roller. The paper feed roller is arranged to face the photoelectric conversion element array, and a white reflective surface is formed on the outer peripheral surface of the paper feed roller, and while the paper feed roller is rotated, reflected light from the reflective surface is reflected. is photoelectrically converted multiple times by the photoelectric conversion element array, and the average variation of these converted values is detected as bit-to-bit variation information. It is in.

[Embodiments of the invention]

Embodiments of the present invention will be described below based on the drawings. Figure 1 shows the schematic structure of a photoelectric conversion device using a line sensor.
2 is a photoelectric conversion element array, 2 is a self-occurring lens array, 3 is a paper feed roller, and 4 is an illumination light source. The optical axis of the self-occurring lens array 2 is perpendicular to the photoelectric conversion element array 1, and the paper feed roller 3 is arranged so that its upper end faces the lower end of the self-occurring lens array 2. . When a document (not shown) is fed onto the paper feed roller 3, the document surface is irradiated with light from the irradiation light source 4, and the image information on the document surface is transmitted to the self-occurring lens array 2 and the photoelectric conversion element array 1. The structure is such that photoelectric conversion is performed in bit units.

Unlike conventional rollers, the paper feed roller 3 has a white reflective surface 5 formed on its entire outer periphery.
When the light from the illumination light source 4 is irradiated onto the reflective surface 5, the reflected light is photoelectrically converted by the self-occurring lens array 2 and the photoelectric conversion element array 1 in the same way as image information. ing.

The photoelectric conversion device is constructed as described above, and information on variations between bits in the photoelectric conversion element array 1 is detected as follows. That is, when the illumination light source is turned on with no document inserted, the reflected light from the reflective surface 5 of the paper feed roller 3 is collected by the self-occurring lens array 2, and then converted into photoelectric converters bit by bit by the photoelectric conversion element array 1. converted.
Variations in this converted value are then transferred to the bit correction circuit as bit-to-bit variation information. Next, the paper feed roller 3 is appropriately rotated, the reading position of the reflective surface 5 is made different from the first time, and photoelectric conversion is performed again. This variation information is transferred to the bit correction circuit, where it is added to the first variation information and averaged. The bit-to-bit variation correction is performed by performing the above operation multiple times, thereby eliminating the influence of the surface condition of the reflective surface 5 of the paper feed roller 3 on the variation information.

In the above embodiment, the reflective surface 5 of the paper feed roller 3 is white, but if it is desired to detect bit-to-bit variation information with respect to black, the reflective surface 5 may be black. Furthermore, if you want to detect the variation information between bits for white and black,
A white reflective surface and a black reflective surface may be formed on the outer circumferential surface of the paper feed roller 3 for half a circumference, respectively.

〔Effect of the invention〕

As described above, the present invention forms a white reflective surface on the outer peripheral surface of the paper feed roller, and while rotating the paper feed roller, the reflected light from the reflective surface is photoelectrically converted multiple times by a photoelectric conversion element array. Since the average variation of these converted values is detected as bit-to-bit variation information, variation information can be easily detected without using a so-called all-white document. In addition, even if the white color of the reflective surface of the paper feed roller is uneven, or even if some dust or the like has adhered to the reflective surface, the system scans multiple locations on the reflective surface and detects the average variation. There is no risk that the reliability of the information will deteriorate. Furthermore, it is also possible to automatically detect dispersion information, and in this case, the prescribed bit correction is performed regardless of the presence or absence of dispersion information between bits, greatly improving the reliability and stability of the photoelectric conversion device. can be improved.

[Brief explanation of drawings]

The drawing is a schematic perspective view of a photoelectric conversion device showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Photoelectric conversion element array, 2... Self-cleaning lens array, 3... Paper feed roller, 4... Illumination light source, 5... Reflective surface.

Claims (1)

[Claims] 1. In a photoelectric conversion device that continuously photoelectrically converts image information on the surface of the document by a photoelectric conversion element array while moving the document illuminated by an illumination light source by a paper feed roller, the paper feed roller is moved. The photoelectric conversion element array is disposed opposite to the photoelectric conversion element array, and a white reflective surface is formed on the outer peripheral surface of the paper feed roller, and while the paper feed roller is rotated, the reflected light from the reflection surface is transmitted to the photoelectric conversion element. 1. A method for detecting variation information between bits in a photoelectric conversion device, characterized in that photoelectric conversion is performed multiple times using an array, and the average variation of these converted values is detected as variation information between bits.